[Variance of bioavailability of pharmaceutical preparations and analysis of factors affecting it].

Phenytoin (pulverized powder), mefenamic acid (capsule), and sulpiride (film-coated tablet) are currently available on the Japanese market. For absorption of these drugs from their pharmaceutical preparations, they must disintegrate and dissolve during passage through the gastrointestinal tract. The bioavailability of these drugs differ among different pharmaceutical preparations and even for the same preparation.

Intra- and interindividual variation in the pharmacokinetics of tacrolimus (FK506) in kidney transplant recipients--importance of trough level as a practical indicator.

Background: Tacrolimus (FK506) is currently used as the primary immunosuppressant in clinical kidney transplantation in some centers. The purpose of this study was to evaluate the pharmacokinetics of this drug and to see if trough level, which has been used widely in therapeutic drug monitoring, can be used as an appropriate substitute for other pharmacokinetic measurement tests.

Methods: The blood concentration-time curve was studied in 10 kidney transplant recipients on 26 occasions after oral dosage of 2 to 18 mg every 12 hours.

Effect of a high-fat meal on the bioavailability of phenytoin in a commercial powder with a large particle size.

The effect of a high-fat meal on the bioavailability of free acid phenytoin (DPH) from Hydantol powder with a large particle size (mean particle size, 190 microns) was investigated in four healthy male subjects. The drug was administered as a single oral 5 mg/kg dose of free acid DPH in the fasting state, with a low-fat meal, or with a high-fat meal using a crossover study design. Seven blood samples were collected over a 34-h period following drug administration, and the drug plasma concentrations were determined by GLC.